AngularJS 的承诺数组

Question

谁能帮我做一些 Angular 的承诺？我有以下函数，它们应该接收一组文件对象，遍历它们，然后上传每个对象。在每次迭代中，promise 对象被推送到promises 的数组中。在我的upload 函数中，我有一个带有.then() 的cycle 函数，在所有promise 对象都解决之前不应调用它。我认为我的代码看起来是正确的，但它不能正常工作。图片上传，但cycle(files).then() 会立即被调用，而不是在promises 数组解析后调用。

function upload(files) {
    var uploadCount = files.length;
    function cycle(files) {
        var promises = [];
        for (var i = 0; i < files.length; i++) {
            var deferred = $q.defer();
            promises.push(deferred);
            var file = files[i];
            Upload.upload({
                url: '/photos.json',
                file: file
            }).success(function(){
                $scope.progressCurrentCount += 1;
                deferred.resolve();
            });
        };
        return $q.all(promises);
    };

    cycle(files).then(function(result) {
        if(uploadCount > 1) {
            $scope.lastAction = 'uploaded ' + uploadCount + ' photos';
        } else {
            $scope.lastAction = 'uploaded ' + uploadCount + ' photo';
        }
        $scope.showSuccessModal = true;
        $scope.uploading = false;
        $scope.failedUploads = [];
        $scope.newPhotos = {
            token: $scope.token,
            files: undefined
        };
        photoUploadBtn.removeClass('disabled');
    })
};

最终工作代码*

与其设置var deferred = $q.defer(); 将deferred.promise 推入promises 数组，然后在我的.success() 回调中解析deferred，这不起作用，我只是推我的Upload.upload() 函数而不使用@ 987654334@ 回调到 promises，然后将其传递给 $q.all()，由它完成所有的提升。

function upload(files) {
    var uploadCount = files.length;
    function cycle(files) {
        var promises = [];
        for (var i = 0; i < files.length; i++) {
            var file = files[i];
            var promise = Upload.upload({
                url: '/photos.json',
                file: file
            });
            promises.push(promise);
        };
        return $q.all(promises);
    };

    cycle(files).then(function(result) {
        if(uploadCount > 1) {
            $scope.lastAction = 'uploaded ' + uploadCount + ' photos';
        } else {
            $scope.lastAction = 'uploaded ' + uploadCount + ' photo';
        };
        $scope.showSuccessModal = true;
        $scope.uploading = false;
        $scope.failedUploads = [];
        $scope.newPhotos = {
            token: $scope.token,
            files: undefined
        };
        photoUploadBtn.removeClass('disabled');
        getPhotos(q);
    })
};

Answer 1

您必须将一个承诺而不是延迟推入promises 数组：

promises.push(deferred.promise);

如果你这样想会有所帮助：

• promise 是您要返回给消费者的只读对象
• deferred 是该只读承诺的修饰符，您希望自己保留它